MARIUPOL, Ukraine — In a makeshift maternity ward in the basement of a Ukrainian hospital, new mother Kateryna Suharokova struggled to control her emotions as she held her son while doctors upstairs raced to treat victims of Russian shelling.

“I was anxious, anxious about giving birth to the baby in these times,” the 30-year-old said, her voice trembling. “I’m thankful to the doctors, who helped this baby to be born in these conditions. I believe that everything will be fine.”

The basement of the maternity hospital in Ukraine’s coastal city of Mariupol transformed into a bomb shelter and nursery as Russian forces escalated their attacks on crowded urban areas Tuesday. Workers bundled one newborn and carried him down flights of stairs to the basement, where a dimly lit room cramped with beds and cribs sheltered workers and patients.

A similar scene unfolded in Kharkiv, where a maternity ward was moved into a bomb shelter. Mothers there rocked newborns in cradles amid mattresses piled against the windows for protection.

Britain’s Defense Ministry said it had seen an increase in Russian air and artillery strikes on populated urban areas in the past few days. Mariupol was one of three cities — along with Kharkiv and Kherson — encircled by Russian forces, the ministry said.

An industrial center on the Azov Sea, Mariupol is seen as a key target for Russian forces for its economic value and its location, which would help Russia establish a land corridor between the Crimean Peninsula and the Russian mainland.

Shelling casualties streamed into the Mariupol maternity hospital, including the body of a young man on a stretcher.

Oleksandr Balash, the head of the anesthesiology department, called to an Associated Press video journalist and lifted a sheet covering the deceased.

“Do I need to say more? This is just a boy,” Balash said. “These are all peaceful citizens who were injured in … a regular neighborhood.”

Another woman, bleeding from the mouth, called out in pain as she was treated. Medical professionals performed surgery on others injured during the shelling, and medics transported a man from an ambulance to a gurney so he could be treated.

Ukrainian President Volodymyr Zelenskyy called the latest attacks a brazen campaign of terror.

In Kharkiv, at least six people were killed when the region’s administrative building on Freedom Square was hit with what was believed to be a missile. The attack on Ukraine’s largest plaza — the nucleus of public life in the city of about 1.5 million — was seen by many Ukrainians as evidence that the Russian invasion wasn’t just about hitting military targets but also about breaking their spirit.

Overall death tolls from the fighting remained unclear, but a senior Western intelligence official estimated that more than 5,000 Russian soldiers have been captured or killed. Ukraine has given no overall estimate of troop losses.